Honors College

Document Type

Honors Thesis

Publication Date



The Gulf of Maine experiences annual closures of shellfish harvesting due to the accumulation of toxins resulting from harmful algal blooms of the dinoflagellate Alexandrium spp. If ingested by humans, these toxins can cause paralytic shellfish poisoning. The factors affecting the timing, location, and magnitude of these events remain poorly understood. Previous work found no obvious correlations between Gulf of Maine oceanographic variability and interannual variability in toxicity in the strongly tidally mixed eastern Maine coastal region in the vicinity of Cobscook Bay. Using 21 years (1985-2005) of Maine Department of Marine Resources shellfish toxicity data, interannual variability in two metrics of annual toxicity, maximum magnitude and integrated total annual toxicity, are examined for relationships to a suite of environmental variables. Consistent with earlier work, no correlation was found between toxicity and oceanographic variables, even when individual station toxicity was compared to very proximate variables such as local sea surface temperature and river discharge. However, correlations between toxicity and two variables indicative of local weather, dew point and atmospheric pressure, both suggest a link between increased toxicity and clearer skies/ drier air. As no correlation was evident between toxicity and local precipitation, we hypothesize that the link is through light availability in this persistently foggy section of coast.